All any factory load reveals is muzzle velocity, not the powder or charge. That's okay because factories don't use cannister powders anyway, they mix and blend what they have tons of to meet their criteria of pressure and velocity.

Unfortunately, that's impossible to answer!
The only ones that know that are Winchester, and even if you could find the recipe, the powder they use is not available to handloaders.
They use a 'bulk' powder that is blended in the laboratory to give the desired ballistics, which is often different to previous loads in a batch.

You can always try to duplicate the velocity, and the nearest powder we have at our disposal is Win Supreme 780. This is very similar to what is loaded in factory loads for the 300.